Effect of the Zeolite Modulus of Pt/MOR/Al_2O_3 Catalysts on the n-Heptane Isomerization Reaction

摘要

The effect of the mordenite acidic modulus (SiO_2/Al_2O_3, 20 and 30) of Pt/MOR/Al_2O_3 catalysts on the heptane isomerization reaction is investigated. The content of zeolite in the catalysts is varied from 10 to 50 wt %, with platinum applied to the samples from solutions of different precursors: H_2PtCl_6 and [Pt(NH_3)_4]Cl_2. It is established via the TPD of ammonia and FTIR spectroscopy (the adsorption of NH_3 and СО) that the total acidity of zeolite falls as the modulus grows: the number of Br?nsted (BAC) and Lewis (LAC) acidic sites is reduced, accompanied by an increase in the strength of their acidity. The catalysts are tested in the n-heptane isomerization reaction. It is shown that the selectivity of n-heptane isomerization falls substantially when the acidic mordenite modulus is increased from 20 to 30.